/errors/bidding_error.proto 

--- v20/errors/bidding_error.proto  2025-08-05 14:39:41.000000000 +0000
+++ v21/errors/bidding_error.proto  2025-08-05 14:39:47.000000000 +0000
@@ -117,5 +117,8 @@

     // cpc_bid_floor_micros is greater than cpc_bid_ceiling_micros.
     CPC_BID_FLOOR_MICROS_GREATER_THAN_CPC_BID_CEILING_MICROS = 41;
+
+    // target_roas_tolerance_percent_millis must be integer.
+    TARGET_ROAS_TOLERANCE_PERCENT_MILLIS_MUST_BE_INTEGER = 42;
   }
 }